Embedded charge technology is being exploited in numerous ways. The underlying science provides a platform for devices that range from micro sensors to macroscopic energy transducers. Embedded charge technology has excellent long-term reliability in environments where the temperature does not exceed a few hundred degrees Celsius.
Embedded charge technology utilizes electronic charge that is trapped at the interface of dissimilar insulators. Typically, systems employ insulators, such as silicon dioxide (SiO2)—silicon nitride (Si3N4), as continuous thin films. For applications in harsh environments with elevated temperatures above a few hundred degrees Celsius there is a need for significant improvement in overall temperature robustness.
An example of prior device 10 for storing embedded charge with charge stored at the interface of dissimilar insulators is illustrated in FIG. 1. The device 10 has a layer of silicon dioxide 14 between a substrate 13 and a layer of silicon nitride 12 and a conductor 15 on the layer of silicon nitride 12. Electronic charge is stored at an interface 16 between the layers 12 and 14. The band gap of the layer of silicon nitride 12 is approximately 5 eV, whereas the band gap of the layer of silicon dioxide 14 is about 9 eV. In this device 10, when electronic charge 18 is stored at the interface 16 of the dissimilar insulators 12 and 14 and the surrounding temperature does not exceed a few hundred degrees Celsius and is not placed in a high electric field, the charge loss mechanism is dominated by Frenkle-Poole conduction through the layer of silicon nitride 12. However, when the surrounding temperature exceeds a few hundred degrees Celsius and/or the device 10 is placed in a high electric field, the retention of the embedded charge 18 in this device 10 deteriorates and the charge 18 can escape to the conductor 15.